You hear over and over that you need to stay hydrated, but what does staying hydrated look like? Here’s how much water you really need to drink.
Keeping our bodies hydrated can sometimes feel more like a chore than a survival instinct. Time and time again, we’ve heard that we’re supposed to drink eight glasses of water a day to comply with a healthy lifestyle. However, the idea of health and hydration is not as straightforward as we’ve been lead to believe. The amount of water we need to drink depends on a variety of factors, including our age, sex, environment, and level of activity.
Let’s start with the most critical thing to be aware of—what dehydration is and feels like.
Side Effects of Dehydration
Low water intake causes dehydration, which has side effects and can cause serious complications if severe. Studies have shown that exercise- and heat-induced mild dehydration, described as the loss of the equivalent of 1-3 percent of body weight, can negatively affect brain function and reduce endurance.
When water levels in the body drop even further, cells are depleted of the fluids they need to carry out their activities, and cognitive functions like memory and attention are impaired. We’re continually losing water through perspiration, respiration, and urination, so it’s good to listen to our bodies and always keep water at hand.
If you feel thirsty, your body is already throwing out the sign that it’s mildly dehydrated. If you start experiencing headaches, muscle cramping, a dry or sticky mouth, or infrequent urination, you’re already moving into more dangerous levels of dehydration and should grab some water.
The Myth of the 8×8 Rule
The rule stating we need to drink eight 8-ounce glasses of water a day to stay hydrated has been a reference point for most of us for years. However, experts don’t agree with it, and the origin of such recommendation is still the subject of debate.
The first appearance of the recommendation dates to 1945 with the publication of the Food and Nutrition Board of the National Academy of Sciences dietary guidelines. The recommendation was to consume 84-oz of water daily, but there was no mentioning of any scientific finding in support of that statement. The idea was then further spread by Frederick J. Stare, a reputable American nutritionist who recommended the consumption of eight 8-ounce glasses of water a day in a book he coauthored in the ‘70s. It wasn’t long before the 8×8 rule became commonly accepted wisdom—despite the lack of any real scientific backing.
While it’s not necessarily harmful advice, there’s no scientific evidence to prove its validity, at least not to the point of making it an official health recommendation.
